Restek CorporationRestek Corporationwww.restekcorp.comwww.restekcorp.com

Improved Phases for the GC Analysis ofChlorinated and Organophosphorus Pesticides

Frank Dorman , Lydia Nolan, and Gary StidsenRestek Corporation110 Benner Circle

Bellefonte, PA 16823

Chlorinated PesticidesFast Runs

Rtx-CLPesticides(30m x 0.32mm, 0.5µm)

Rtx-CLPesticides2(30m x 0.32mm, 0.25µm)

1

2 3

4

5

67

8 9

10

11

12

13

14 15

16

1718

19

2021

22

1

2 3

4

5

67

8 9

10

11

1213

14 1516

1718

19

2021

22

6 8 10 12

6 8 10 12

Chlorinated PesticidesSiltek Deactivation

Stx-CLPesticides(30m x 0.32mm, 0.5µm)

Stx-CLPesticides2(30m x 0.32mm, 0.25µm)

1

23

4

5

67 8 9

10

11

12

1314

15

1617 18

19

2021

22

1

2 3

4

56

78 9

10

11

12

13

1415

161718

19

20

21

22

6 8 10 12

6 8 10 12

14

14

Chlorinated PesticidesAnalytical conditions

GC oven: 120°C(1min) up at 20°C /min to 245°C,up at 6°C /min to 310°C

Injector: 220°C, splitless, 1min purge off hold,4mm single gooseneck Siltek sleeve

Detector: 310°C, Agilent ECD

Column: Stx-CLPesticides on Siltek, cat# 11544

30m x 0.32mmID, 0.5µm

Rtx-CLPesticides, cat# 11139

30m x 0.32mmID, 0.5µm

Column: Stx-CLPesticides 2 on Siltek, cat# 11444

30m x 0.32ID, 0.25µm

Rtx-CLPesticides 2, cat#11324

30m x 0.32mmID, 0.25µm

RT# Analyte1 2,4,5,6 tetrachloro-m-xylene - surrogate2 alpha-BHC3 gamma-BHC4 beta-BHC5 delta-BHC6 heptachlor7 aldrin8 heptachlor epoxide9 gamma-chlordane

10 alpha-chlordane11 4,4' DDE12 endosulfan I13 dieldrin14 endrin15 4,4' DDD16 endosulfan II17 4,4' DDT18 endrin aldehyde19 methoxychlor20 endosulfan sulfate21 endrin ketone22 decachlorobiphenyl - surrogate

Organophosphorus Pesticides

Rtx-OPPesticides(30m x 0.32mm, 0.5µm)

Rtx-OPPesticides2(30m x 0.32mm, 0.32µm)

1 2

3

4 5

6

7,8

9

10

11

12

13

14

15

1617

18

18

19,20

21

22

6 9 12

23

24

25

2627

28

29

30 31 50

32,33

34

35

3637

3839

40 42

4344 45

46

47 4849

41

51 52 53

15 18 21

1

2

3

4

5

6

7

9,10,11

12

13

15

14

16

17

18

9 12 15

19

20,21,22

23

24,25

26,27

28

29

30

3150

32

34

35

36,3739,40

42,43

44

4546

47 48

4941

51 52 53

18 21 24

8

33

38

Organophosphorus PesticidesRetention Comparison

RT# Analyte - RTX-OPP2 Analyte - RTX-OPP1 dichlorvos dichlorvos2 hexamethylphosphoramide hexamethylphosphoramide3 mevinphos trichlorfon4 trichlorfon mevinphos5 TEPP demeton-o6 demeton-o thionazin7 tributyl phosphate -surrog ethoprop8 thionazin phorate9 ethoprop tributyl phosphate -surrog

10 naled sulfotepp11 sulfotepp naled12 phorate diazinon13 dicrotophos terbufos14 monocrotophos TEPP15 demeton-s fonophos16 terbufos dioxathion17 dimethoate disulfoton18 diazinon demeton-s

GC oven:80°C(0.5min)up12°C/min to280°C(15min)

Injector: 200°C splitless, purgeoff time 1min, 4mm singlegooseneck Siltek sleeve

Detector: Agilent FPD 250°CDT @80c=1.44min, heliumcarrier

Columns:RTX-OPPesticides, cat# 1123930m x 0.32ID, 0.5um

RTX-OPPesticides2, cat# 1124130m x 0.32ID, 0.32um

Organophosphorus PesticidesRetention Comparison

RT# Analyte - RTX-OPP2 Analyte - RTX-OPP19 dioxathion dichlorofenthion20 fonophos chlorpyrifos methyl21 disulfoton dimethoate22 phosphamidon isomer monocrotophos23 dichlorofenthion dicrotophos24 phosphamidon merphos25 chlorpyrifos methyl ronnel26 parathion-methyl chlorpyrifos27 ronnel aspon28 aspon fenthion29 fenitrothion trichloronate30 malathion phosphamidon isomer31 chlorpyrifos malathion32 parathion-ethyl parathion-methyl33 trichloronate fenitrothion34 fenthion tokuthion35 merphos phosphamidon36 chlorfenvinphos merphos oxone

Organophosphorus PesticidesRetention Comparison

RT# Analyte - RTX-OPP2 Analyte - RTX-OPP37 crotoxyphos chlorfenvinphos38 stirofos parathion-ethyl39 tokuthion crotoxyphos40 merphos oxone stirofos41 ethion bolstar42 fensulfothion carbophenothion43 bolstar ethion44 carbophenothion triphenyl phosphate -surrogate45 famphur leptophos46 triphenyl phosphate -surrogate fensulfothion47 EPN tri-o-cresyl phosphate48 phosmet EPN49 leptophos phosmet50 tri-o-cresyl phosphate famphur51 azinphos-methyl azinphos-methyl52 azinphos-ethyl azinphos-ethyl53 coumaphos coumaphos

Organophosphorus Pesticides: MS DataGC oven: 80°C (0.5min) up12°C/min to

280°C (15min)

Injector: 200°C splitless, hold time 1min,4mm single gooseneck Siltek sleeve

Detector: Agilent 5971A MSDfull scan 50-550AMU

DT @80°C=1.44min, helium carrier

Column: RTX-OPPesticides2, cat# 1124130m x 0.32mmID, 0.32µm

9 12 15 18 21

Organophosphorus PesticidesMS Spectra Rtx-OPPesticides2

(30m x 0.32mm, 0.32µm)

parathion-ethyl trichloronate

Organophosphorus PesticidesMS Spectra Rtx-OPPesticides2

(30m x 0.32mm, 0.32µm)

tributyl phosphate thionazin

Organochlorine Pesticides

•• Chromatographic resolution of USEPA 8081Chromatographic resolution of USEPA 8081compoundscompounds

•• RtxRtx--CLPesticides andCLPesticides andRtxRtx--CLPesticides2 columnsCLPesticides2 columns

•• Dual column configurationDual column configuration

•• Low bleedLow bleed

•• High inertnessHigh inertness

•• Faster analysis timesFaster analysis times

Chlorinated Pesticides

1 2,4,5,61 2,4,5,6--tetrachlorotetrachloro--mm--xylenexylene2 alpha BHC2 alpha BHC3 gamma BHC3 gamma BHC4 beta BHC4 beta BHC5 delta BHC5 delta BHC6 heptachlor6 heptachlor7 aldrin7 aldrin8 heptachlor epoxide8 heptachlor epoxide9 gamma chlordane9 gamma chlordane10 alpha chlordane10 alpha chlordane11 4,4'11 4,4'--DDEDDE

12 endosulfan I12 endosulfan I13 dieldrin13 dieldrin14 endrin14 endrin15 4,4'15 4,4'--DDDDDD16 endosulfan II16 endosulfan II17 4,4'17 4,4'--DDTDDT18 endrin aldehyde18 endrin aldehyde19 methoxychlor19 methoxychlor20 endosulfan sulfate20 endosulfan sulfate21 endrin ketone21 endrin ketone22 decachlorobiphenyl22 decachlorobiphenyl

Rtx®-CLPesticides Column

10 12 14 16 18 20 22

1

2 3

4

5 6 78 9

10

11

12

13

14

15

16

1718

19

20

21

22

30m, 0.32mm ID, 0.5µm, Rtx®-CLPesticides; EPA 8081 list, direct injection, Uniliner® liner(cat. #20335). Oven temp.: 120°C (hold 1 min.) to 300°C @ 9°C/min. (hold 10 min.); Inj. temp.:200°C; Dead time: 1.797; Head pressure: 5.0psi (constant); Flow rate: 2.1mL/min. at 120°C.

Rtx®-CLPesticides2 Column

10 12 14 16 18 20 22 24

12 3

4

5

6

78 9

10 12

1113

14

1516

17 18

20

19

21

22

30m, 0.32mm ID, 0.25µm Rtx®-CLPesticides2; EPA 8081 list, direct Uniliner® sleeve(cat. #20335). Oven temp.: 120°C (hold 1 min.) to 300°C @ 9°C/min. (hold 10 min.);Inj. temp.: 200°C; Dead time: 1.797; Head pressure: 5.0psi (constant); Flow rate:2.1mL/min. @ 120°C.

Siltek Deactivation

•• SurfaceSurfacemodificationmodification, not deactivation layer, not deactivation layer–– Does not attach to existingDoes not attach to existingsilanolsilanolgroupsgroups

•• Higher level of inertness forHigher level of inertness forEndrinEndrin

•• More resistant to acid or base attackMore resistant to acid or base attack–– Stays inert for longer timeStays inert for longer time

•• More easily cleanedMore easily cleaned–– Solvent rinsing usually acceptableSolvent rinsing usually acceptable

Requirements of Organophosphorus Column

•• Chromatographic separation of USEPA 8141Chromatographic separation of USEPA 8141compoundscompounds

•• Companion column toCompanion column toRtxRtx--OPPesticidesOPPesticides

•• 20 minute total run time20 minute total run time

•• Also compatible withAlso compatible withGC/MSGC/MS analysisanalysis–– Low BleedLow Bleed

–– Resolution of compounds with similar spectraResolution of compounds with similar spectra

“Old Days of GC”

•• Chromatography has become a “history lesson”Chromatography has become a “history lesson”rather than a sciencerather than a science

•• Applications compromised to fit existing columnsApplications compromised to fit existing columnsand stationary phasesand stationary phases

•• Most phases not designed with any application inMost phases not designed with any application inmindmind

•• Marketing based on “subtle” differencesMarketing based on “subtle” differences

Future of GC

•• Columns and stationary phases designedColumns and stationary phases designedaround applicationsaround applications

•• Potential for specific phase and column for anPotential for specific phase and column for anindividual separationindividual separation

•• Marketing based on real differencesMarketing based on real differences

•• Requires understanding and ability to model ofRequires understanding and ability to model ofanalyteanalyte--phase interactionsphase interactions

Stationary Phase Optimization Techniques

•• WindowWindow diagrammingdiagramming

•• ComputerComputersimulationsimulationof Rt and Wof Rt and W1/21/2 (ezGC(ezGCTMTM))

•• ComputerComputerpredictionpredictionofof optimizedoptimizedstationarystationaryphasephasecompositioncompositionandandcolumncolumndimensionsdimensions

•• ComputerComputerpredictionpredictionofof solutesolute//stationarystationaryphasephaseinteractionsinteractionsforfor newnewpolymerpolymerdesignsdesigns

How Resolution Affects QuantitationVRX phase

Results of Resolution Tests @ 20ppb

MeCl2 & Freon 113 Rep 1 19.85 18.48Rep 2 19.29 18.48Rep 3 19.36 18.52

Methylene Chloride Rep 1 21.48Rep 2 20.79Rep 3 20.95

Freon 113 Rep 1 16.3Rep 2 16.46Rep 3 16.25

Achieving Analyte Separation

ResolutionResolutionR = 1/4 L / h x ( k / k+1 ) x (R = 1/4 L / h x ( k / k+1 ) x ( αααααααα--1 /1 / αααααααα ))

Capacity FactorCapacity Factork = (tk = (t RR -- tt00) / t) / t00

SelectivitySelectivityαααααααα = k= k22 / k/ k11

Thermodynamics:Thermodynamics:∆∆∆∆∆∆∆∆G =G = ∆∆∆∆∆∆∆∆HH -- TT∆∆∆∆∆∆∆∆SS ∆∆∆∆∆∆∆∆G = RT ln KG = RT ln K DD

Stationary Phase Optimization

•• WindowWindow diagrammingdiagramming

•• ComputerComputersimulationsimulationof Rt and Wof Rt and W1/21/2 (ezGC)(ezGC)

•• RtxRtx®®--CLPesticides,CLPesticides,RtxRtx--CLPesticides2CLPesticides2

•• ComputerComputerpredictionpredictionofof optimizedoptimizedstationarystationaryphasephasecompositioncompositionANDAND columncolumndimensionsdimensions–– RtxRtx--TNT RtxTNT Rtx--TNT2, RtxTNT2, Rtx--VMS, RtxVMS, Rtx--VGC, RtxVGC, Rtx--5SilMS, Rtx5SilMS, Rtx--

VRX,VRX, RtxRtx--OPPesticides2, CustomerOPPesticides2, Customer--specific columnsspecific columns

•• ComputerComputerpredictionpredictionofof solutesolute//stationarystationaryphasephaseinteractionsinteractionsforfor newnewpolymerpolymerdesignsdesigns

Process for Rtx-OPPesticides2 Column

•• Acquire data for target compounds under twoAcquire data for target compounds under twotemperature programs for functionalitiestemperature programs for functionalitiesdisplaying selectivitydisplaying selectivity

•• Computer Assisted Stationary Phase DesignComputer Assisted Stationary Phase Design(CASPD)(CASPD)–– CalculateCalculate∆∆H andH and∆∆SS for each compoundfor each compound

–– Working in Retention Index, perform optimization ofWorking in Retention Index, perform optimization ofSelectivity and DimensionsSelectivity and Dimensions

•• Synthesize and coat columnSynthesize and coat column

3-Space Selectivity Model for 3 Compounds

End-on View of Selectivity Model

0

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4

6

8

10

12

14

16

18

0 10 20 30 40 50 60 70 80 90 100

% Composition

Ret

entio

nT

ime

Compounds 1 – 25 of 53 OP PesticidesTarget Predicted Actual Difference

Compound Rt Rt (min)dichlorvos 4.08 4.05 -0.03

HMPA 4.70 4.70 0.00mevinphos 6.43 6.34 -0.09trichlorfon 6.44 6.43 -0.01

TEPP 8.20 8.40 0.20demeton-o 8.46 8.52 0.06thionazin 8.58 8.52 -0.06

TBP 8.60 8.52 -0.08ethoprop 8.84 8.74 -0.10

naled 9.34 9.32 -0.02sulfotepp 9.42 9.56 0.14phorate 9.53 9.56 0.03

dicrotophos 9.61 9.59 -0.02monocrotophos 9.70 9.62 -0.08

demeton-s 9.80 9.62 -0.18terbufos 10.44 10.32 -0.12

dimethoate 10.67 10.62 -0.05dioxathion 10.78 10.77 -0.01fonophos 10.91 10.79 -0.11diazinon 10.93 10.90 -0.04disulfoton 11.13 11.09 -0.03

phosph isomer 11.19 11.16 -0.04dichlorofenthion 11.38 11.37 -0.01

chlorpyrifos methyl 11.94 12.03 0.09phosphamidon 12.14 12.03 -0.11

Summary

•• RtxRtx--CLPesticides andCLPesticides andRtxRtx--CLPesticides2 columnsCLPesticides2 columnsutilizingutilizing Siltek™Siltek™ deactivationdeactivationprovideprovideultimateultimateseparation ofseparation oforganochlorineorganochlorinepesticides.pesticides.

•• RtxRtx--OPPesticidesOPPesticidesandandRtxRtx--OPPesticides2 columnsOPPesticides2 columnsare optimal dual column pair for USEPA 8141.are optimal dual column pair for USEPA 8141.

•• RtxRtx--OPPesticides2 column best for separation ofOPPesticides2 column best for separation oforganophosphorousorganophosphorouspesticides bypesticides byGC/MSGC/MS..